Skip to main content

Full text of "New species of Devonian fossils from western Illinois"

See other formats


\3 Biodiversity 
^Heritage 
^^Library 

http://www.biodiversitylibrary.org/ 



Transactions of the Illinois State Academy of Science. 

Springfield, III., Illinois State Academy of Science [etc.] 
http://www.biodiversitylibrary.org/bibliography/15333 



v.1 4-1 5 1 921 -1 922 : http://www.biodiversitylibrary.org/item/52422 

Page(s): Title Page, Table of Contents, Page 197, Page 198, Page 199, Page 200, Text, Text, 

Text, Text, Page 201 , Page 202, Page 203, Page 204, Page 205, Page 206 



Contributed by: Mertz Library, The New York Botanical Garden 
Sponsored by: The LuEsther T Mertz Library, the New York Botanical Garden 



Generated 16 November 2011 11:10AM 
http://www.biodiversitylibrary.org/pdf3/008651900052422 



This page intentionally left blank. 



TRANSACTIONS 



OF THE 



llinois State Academy of Science 



FOURTEENTH ANNUAL MEETING 



Southern Illinois State Normal University 

Carbondale, Illinois 

April 29th and 30th, 1921 



VOLUME XIV 



[Published by Authority of the State of Illinois | 



TABLE OF CONTENTS 



Officers and Committees for 19214922. 

Past Officers of the Academy ..,.......*.... 



PAGE 

■ ■ • ' • V 



• •*•***-•* 



Report of the Secretary . . * . 

Minutes of the Foukteenth Annual Meeting..,. 



*1. «*••**- 



Treasurer's Report . . . . - 

Papers of General Interest: — Invitation Addresses; 

Some Events in the Geological History of Southern Illinois: Stoart 
Weller. University of Chicago...', - 

The Geography of the Ozarks: Frank H. Colyer. Southern Illinois 
State Normal University. Caxbondale ••*•••• 

Undeveloped Resources of Southern Illinois: R, B, Miller, State 
Forester. Natural History Survey Division. Urbana..,.., 

The Lore of the Southern Illinois Ozarks: Clarence Bonnell, Town- 
ship High School. Harrisburg. . . 



9 
11 

17 



**»*•*»•*•»*•***■ + « 



21 



36 



45 



SO 



Papers on Biology and Agriculture: 

Some Plants of the Bois Fort Indian Reservation and Vicinity in 
Minnesota: Albert R Reagan. Kayenta* Arizona 

A Trip Among the Bird Islands of the Pacific Coast of Washington: 
Albert B. Reagan. Kayenta, Arizona 

Preliminary Report of the Bog? of Northern Illinois: W. G* Water- 
man, Northwestern University, Evanston. . , 

Note on Juvenile Leaves in Thuja Occidentals: W. G, Waterman. 
Northwestern University, Evanston 

A Preliminary Key to Some Forest Tree Roots: W. B. McDougall. 
University of Illinois, Urbana . . 

Forest Conditions in Alexander County, Illinois: R. B. Miller, State 
Forester, Urbana, and Geo. D. Fuller. University of Chicago.*.* 

Growth as Related to Specific Gravity and Size of Seed: Mary E* 
Renick, Illinois State Normal University. Normal. . . . . . 

A Metrical Study of a Thousand Moth Cocoons: E. R. Downing, 

The Agricultural Significance of the Tight Clay Subsoil of Southern 
Illinois: fL S. Smith. Agricultural College. University of Illinois, 
Urbana, and F, A. Fisher. Farm Advisor. Wabash County. Illinois 

The Plant Ecology of the Rock River Woodlands of Ogle County, 
Illinois: H. De Forest, Universitv of Chicago. 1920 



61 



71 



79 



85 



87 



92 



109 



140 



..... i 



142 



152 



Papers on Geolocy and Geography: 

New Species of Devonian Fossils from Western Illinois; T. E. Savage. 

University of Illinois, Urbana 197 

Work of the Illinois State Geological Survey: James H. Hance, Stale 

Geological Survey. Urbana 207 

The Glacial History of the Sangamon River Valley at Decatur and its 
Bearing on the Reservoir Project: Morris M. Leighton, State 
Geological Survey, Urbana 213 

The Effects of Faults and Dikes in the Saline County Coal Field: 

Clarence BonnelL Harrisburg Township High School, Harrisburg 219 



PAPERS ON GEOLOGY AND GEOGRAPHY 



197 



NEW SPECIES OF DEVONIAN FOSSILS FROM 

WESTERN ILLINOIS 

Prof. T. E. Savage, University of Illinois 

The Devonian limestones of Rock Island County, Illi- 
nois, were deposited in a basin that was connected north- 
westward with the Arctic Ocean, and are said to belong to 
the northern or Interior Continental province. They are 
an eastward continuation of the Devonian limestones of 
eastern Iowa, with which they entirely correspond. These 
limestones in Iowa were described by Owen 1 in 1852 as 
"The limestones along Cedar Valley 1 ", and he considered 
them equivalent to the upper Helderberg (Onondaga) and 
Hamilton formations of the New York section. 

James Hall- in 1858 also referred the Devonian lime- 
stones in Iowa to the upper Helderberg (Onondaga) and 

Hamilton formations. 

In a report on the Geology of Iowa in 1870 White 8 as- 
signed all of the Devonian limestones of Iowa to the 
Hamilton formation, under which name the strata were 
described. 

Three years later Hall and Whitfield* restudied the De- 
vonian Limestones of Iowa and correlated the limestone 
in the vicinity of Waterloo with the upper Helderberg 
(Onondaga) ; the white limestone near Raymond with the 
Schoharie; and the limestones at Waverly and Indepen- 
dence with the Hamilton of New York. 

In 1878 Calvin 5 referred the Devonian limestones in 
eastern Iowa to the Hamilton formation. 

Barris, 6 who had studied the Devonian limestones in the 
vicinity of Davenport and Rock Island, reported one or 
more unconformities in those beds and considered the up- 
per limestones of that region equivalent to the Hamilton of 
New York, and the earlier Devonian limestones to the up- 
per Helderberg (Onondaga). 



1 Owen, D. D., Rept. Geol, Surv. Wis., Iowa and Minn., pp. 77-89, 1852. 

2 Hall, James., Geol. of Iowa, Vol. I. pt. I. pp. 81-88, 1858. 

3 White. C. A., Geol. of Iowa, Vol. I, p. 109, 1870. 

4 Han, James and Whitfield, R. P.. 23rd. Ann. Rept. of Regents of N. Y. State 
Cabinet, pp. 223-226, 1873. 

5 Calvin, Samuel. Am. Jour, of Science. 3rd ser. Vol. 15. pp. 460-ifi2. 

6 Barris. James, Proc. Davenport, Acad, of Science, Vol. 2, pp. 2fil-2*>9 and 
282-288, 1870. 



198 ILLINOIS STATE ACADEMY OF SCIENCE 

In volume I. of the reports on the Geological Survey of 
Illinois Worthen 7 referred the Devonian limestones of Rock 
Island County, Illinois, to both the upper Helderberg 
(Onondaga) and the Hamilton formations. In discussing 
the Geology of northeastern Iowa in 1891 MaGee 8 con- 
sidered the Devonian limestones as a unit and revived the 
name "Cedar Valley limestones" applied by Owen to these 
strata more than 40 years before. MaGee proposed to dis- 
tinguish the lower, brecciated member of these limestones 
as the "Fayette breccia" from the town of Fayette, Iowa, 
where they are well exposed. 

The same year Calvin 9 gave the name Gyroceras beds 
to the strata a few feet in thickness lying immediately above 
the brecciated limestones containing many Gyroceroid 
shells. 

In 1895 Norton 10 proposed the name Wapsipinicon lime- 
stone for the Devonian strata included in the Fayette brec- 
cia of MaGee, and the Gyroceras beds of Calvin, from the 
Wapsipinicon River in eastern Iowa where these rocks 
are well exposed. He restricted the name Cedar Valley 
limestone to the more shaly and very fossiliferous strata, 
that occur above the Gyroceras beds in eastern Iowa. 
Norton 11 also divided the Wapsipinicon limestone into the 
following members: Otis beds at the base; Kenwood 
shale; Lower Davenport limestone, equivalent to the 
Fayette breccia of MaGee; and Upper Davenport lime- 
stone, corresponding to the Gyroceras beds of Calvin. 
This classification has generally been followed by the Iowa 
Geological survey. Weller 12 has considered the Wapsipini- 
con limestone of Iowa in the main equivalent in time to the 
later Hamilton of the New York section and the Cedar Val- 
ley limestone about contemporaneous with the Portage 
group of New York. 

The writer 13 has recently correlated all of the Cedar Val- 
ley and Wapsipinicon limestones of Iowa and Illinois about 

7 Worthen, A. H.. Geo). Surv. of Illinois, Vol. 1, p. 120, 1866. 

8 MaGee, W. J., Eleventh Ann. Rept. U. S. Geol. Surv., p. 319, 1891. 

9 Calvin, Samuel, Am. Geologist, Vol. VII T, p. 142, 1891. 
If! Norton, W. H., Iowa Geol. Surv., Vol. IV, p. 155, 1895. 

11 Norton, \\\ H., Proe. Iowa Aead. of Science, Vol. I. pt. 4, pp. 22-24, 1893. 

12 Weller, Stuart, Outlines of Geological History with Especial Reference to 
North Am., p. 101, 1910. 

13 Savage, T. E., Devonian Formations in Illinois, Am, Jour, of Science, 4th 
Scr., Vol. 49, Mch., pp. 181 and 182, 1920. 



PAPERS ON GEOLOGY AND GEOGRAPHY 



199 



with the Tully limestone of the New York section. The 
Wapsipinicon and Cedar Valley limestones are both pre- 
sent in Rock Island County, Illinois, and the following mem- 
bers of the Wapsipinicon limestone are recognized in that 
region: Otis beds; Lower Davenport limestone; and Up- 
per Davenport limestone. 

WAPSIPINICON LIMESTONE 

The Otis Beds outcrop on Campbell's Island in the Mis- 
sissippi River above Moline, and a few low exposures oc- 
cur in the Illinois bank of the River in that vicinity. This 
is gray to dark non-magnesian limestone, commonly rather 
fine grained, and somewhat irregularly bedded. The thick- 
ness does not exceed 15 or 20 feet. It is succeeded in this 
region by the Lower Davenport limestone without any 
trace of the Kenwood Shale. The Lower Davenport mem- 
ber consists of strongly brecciated nonfossiliferous lime- 
stone, the fragments of which are gray to dark, fine 
grained, and show fine laminations on weathered surfaces. 
The matrix is also fine grained, but is somewhat lighter in 
color. This brecciated limestone is exposed in the Govern- 
ment Island at Rock Island, and is the horizon formerly 
quarried in Rock Island and Moline. The Lower Daven- 
port limestone is overlain in apparent conformity by the 
Upper Davenport member which is composed of gray, 
granular, subcrystalline limestone, in irregular layers 
from a few to twelve inches or more in thickness, and con- 
tains several fossils, among which Phillipsastrea billingsi, 
Diplophyllum major, Schizophoria macfarlanei, Gypidula 
comis, and several Cephalopod species are characteristic. 
This member is well exposed in the vicinity of Sears and 
Milan. 

CEDAR VALLEY LIMESTONE 

The Cedar Valley limestones are commonly more shaly, 
more evenly beaded, and more richly f ossilif erous than those 
of the Wapsipinicon which they succeed without any sedi- 
mentary break. They outcrop in the banks of Mill Creek, 
and farther west along several of the creeks both east and 
west of Andalusia. These limestones are commonly rather 
thin bedded, shaly and obliquely jointed in the lower part. 



200 ILLINOIS STATE ACADEMY OF SCIENCE 

The Acervularia coral reef is near the middle, above which 
the layers are mostly limestone or dolomite. The total 

thickness of the formation is nearly 70 feet. 

The general succession and relations of the Devonian 
rocks in Rock Island county are shown in the following 
section : 

Generalized section of the Devonian rocks in the vicinity 
of Rock Island, Illinois: 

CEDAR VALLEY LIMESTONE. Feet 

10. Dolomite, yellowish-gray to brown, in layers 6 to 24 inches thick, 
alternating with thinner partings of shale, containing many 
stromatoporoids and other fossils. Exposed along the creeks 
both east and west of Andalusia 20 

9- Limestone, thin bedded, gray, with partings of shale, containing 
many stromatoporoids 5 Stropheodonta demissa, Schizophoria 
iowensis, Athyris fultonensis, Atrypa reticularis (large shells), 
Gomphoceras cf. ajax, and other fossils. Exposed near the months 
of a few streams near Andalusia * 4 

8. Dolomite, yellowish-gray, in layers 12 inches or less, containing 
Cystodictya hamiltonesis, Athyris fultonensis, Spirifer asper, 
S. sebvaricosus, Cyrtina hamiltonensis, small shells of Atrypa 
reticularis and other fossils, . , , * • . . . • 6 

7. Limestone, the upper V/i feet the Acervularia davidsoni coral 
reef. The lower part is an organic breccia which in places pro- 
jects by intersecting vertical plates into the underlying layer. 
Exposed in the bank of the river below Andalusia, and in the 
bank of Mill Creek near the center of Section 25, T. 17 N, 
R. 2 W. .•■• * '"••• 8 

6. Limestone, impure, bluish-gray, crinoidal, thin bedded, con- 
taining Cladopora iowensis, Megistocrinus latus, Ghonetes scitu- 
lus, Leptostrophia perplana, Spirifer asper, S. iowensis, S« sub- 
varicosus* Cyrtina umbonata, and other fossils. Exposed at the 
most of the localities where the overlying coral reef outcrops 5 

5. limestone, blue, argillaceous, fine grained, with very oblique and 
prominent jointing. Containing Spirifer iowensis, S. subvaricosus, 
Cyrtina umbonata, Atrypa aspera var. hystrix, and other fossils. 
Exposed along Mill Creek; and in the quarries near Linwood 
and Buff alo : in Iowa ..-•*•». ■ •' 20 

4, Limestone, fine-grained, rather thin bedded, with shaly partings, 
containing Acervularia profunda, Favosites alpenensis, Schizo- 
phoria iowensis, Pentamerella dubia, Pro duct ell a subalata, 
Spirifer asper, S. bimesialis, and S. iowensis. Exposed in the 
quarries and ledges in Rock Island, Sears and Milan, 5 

WAPSIPINICON LIMESTONE. 
Upper Davenport Beds). 
3. Limestone, hard, gray, in imperfect layers 6 to 24 inches thick, 
containing Astraeospongia hamiltonensis, Chonophyllum^ cf. 
magnificum, Diplophyllun major, Phillipsastrea billingsi, 
Spirifer subundiferous, and other fossils, exposed near the rail- 
road bridge across Mill Creek, and near the wagon bridges across 
Rock River. This is the horizon formerly worked in the old 
quarries in Milan and Rock Island . , . 8 



PLATE I 




PLATE II. 







k 







r 



7 








4-' 





G 



// 





PLATE III. 



L 




/ 



PLATE IV 







' 



T <i 







■f 



*% 



i 



S 



. 



I 



-& 







■ ■ 




> > 




i ** 



/ 



PAPERS ON GEOLOGY AND GEOGRAPHY 



201 



Lower Davenport Beds. 

2, Limestone, white to dark gray, fine grained, in layers J A to 3% 
feet thicks with few fossils, in places finely laminated, usually 
much fractured and breeeiated, with fragments 1 to 24 inches in 
diameter- Exposed in the Cady quarries in East Moline, in the 
the Government Island* in the south bank of Mississippi River 
in Rock Island, and forms the bed rock in Rock River valley 
between Milan and Sears — fossils few or none, . . . 

OTIS LIMESTONE. 

1. Limestone, light to dark gray, fine grained, not brecciated. in 
irregular layers, containing spherical concretions of chalcedonic 
quartz, and numerous shells of Martinia subumbona. Exposed on 
the east side of Campbell's Island above Moline. and in the east 
bank of Mississippi River opposite the island 



55 



20 



ZAPHRENTIS PUTILLA N. SP. 

Plate I. Figures 3 and 4. 

Description :— Corallum simple, conical straight or slightly curved, sub-cir- 
cular in cross-section, diameter increasing gently and at a rather uniform rate 
from the apex. Surface marked by rather distinct septal furrows, and by oc- 
casional transverse wrinkle?, or ridges and depressions, which are usually 
small: rim of calyx thin, very little oblique; the calyx moderately deep con* 
tracted below, with a rather large fossula; major septa commonly about 24. 
ranging from 20 to 30, depending on the size or age of the corallite. their 
inner extremities nearly or quite reaching the center; alternating w r ith the 
major septa are an equal number of low, secondary, septa which are some- 
times scarcely more than septal ridges. 

The dimensions of two individuals are: Length 20 to 30 mm., diameter of 
calyx 10 to 14 mm. 

■r 

This species differs from most species of Zaphrentis in its small size, the 
slight, if any, curvature, and the very gradually expanding corallum. It lacks 
the pseudecolumella or vesiculose central area of Stereolasma rectum Hall. 
and Streptelasma strictum HalL with which it most nearly corresponds in 
size. It is distinguished from Zaphrentis calcareforme in that the shorter septa 
do not join the longer, and the latter are not united with the wall of the fossula. 

Horizon and Locality: — Common in the Cedar Valley limestone along Mill 
Creek, near Milan, where it occurs a few feet below the Acervularia coral reef, 

DIPLOPHYLLUM? MAJOR N. SP. 

Plate I, Figures 1 and 2. 

Description: — Corallum compound, in rather dense masses 1 to 2 feet in 
diameter. The corallites are cylindrical, more or less parallel, nearly con- 
tiguous or separated from one another by a distance less than the width of 
the corallites. not connected by prolongations of the epitheca, circular in cross 
section, varying from 8 to 12 mm. in diameter; marked on the surface by 
indistinct longitudinal lines resembling septal ridges, and also hy fine trans- 
verse lines, and rather strong annulations and constrictions. The calyx is 
moderately deep, septa about 40, more or less undulating, half of them longer 
than the others and joined together irregularly at the center, or uniting near 
the center, to form an inner ring or wall surrounding a small central area. 
The alternate or secondary septa are shorter than the primary ones, and ex- 
tend slightly more than half the distance from the periphery to the center; thf* 
disseppiments are numerous, and the septa carinated in the outer zone through 
which both sets of septa extend: a few disseppiments are present in the more 
open, centra] zone penetrated only by the longer septa. A few of the corallites 
— about 1 out of every 5 in the same corallum,— show a ?mall central area 
about 1 millimeter in diameter surrounded by a distinct wall formed by the 



202 ILLINOIS STATE ACADEMY OF SCIENCE 

coalescence of the inner edges of the longer septa, the other four-fifths of 
the corallites show no such central area, the inner edges of the longer septa 
uniting Irregularly in the central part of the corallite without forming a defi- 
nite ring. 

Horizon and Locality: — Common in the upper part of the Wapsipinicon 
limestone in the vicinity of Milan, where it is associated with Phillipsastrea 
billingsi, Gypidula comis, and the eephalopods described on a later page of 
this paper. 

RHIPIDOMELLA MINIMA N. SP. 
Plate II, Figures 1 and 2. 

Description: — Shell small, biconvex, length and width about equal, the 
greatest width anterior to the middle; hinge line about equal to J4 the greatest 
width of the shell; the cardinal extremities rounded. Ventral valve most convex 
in the umbonal region from which the surface curves rather abruptly to the 
cardinal margin, and more gently to the lateral and anterior margins; without 
trace of mesial fold or sinus, beak small, extending only a short distance above 
the hinge line; cardinal area small, concave, its margins sharply defined; del- 
thyrium rather broadly triangular. Dorsal valve not quite so convex as the 
ventral, the greatest convexity posterior to the middle from which the surface 
slopes gently in all directions, the median portion of the valve depressed into 
a distinct sinus which begins near the beak, and becomes stronger anteriorly 
but is po'orly defined laterally; the beak is small, not incurved; cardinal area 
very narrow, lying almost in the plane of the valve* 

The surface of both valves marked by numerous radiating striae which begin 
near the beak, and bifurcate 3 or 4 times before reaching the front margin 
where about 3 are present in a distance of one millimeter. These striae are 
strongest and subangular on the unbones, decreasing somewhat in size towards 
the front, A few concentric lines of growth are present near the front and 
lateral margins. 

The dimensions of the shell are; Length 8 to 11 millimeters, greatest width 
8 to 11 millimeters, thickness 3 to 3,5 millimeters. 

Remarks: — In the small size, and in the mesial sinus of the dorsal valve 
this species resembles Rhipidomella jerseyensis described by Weller from the 
Kinderhood of Illinois and Missouri. It differs from that form in its typically 
smaller size, the more nearly circular outline, the more angular and stronger 
striae on the unbones, and the few r er and coarser striae over the surface of the 
shell, the more concave or arched cardinal area of the vertical valve, the less 
compressed cardinal extremities, and the more rounded front margin which 
is not emarginate. 

From Rhipidomella dubia (Hall) it is distinguished by the broader posterior 
portion, more circular outline, longer hinge line, and the presence of a mesial 
sinus in the dorsal valve, and its absence in the ventral* 

From R. tenuicosta Weller from the Kinderhook our species differs in hav- 
ing coarser striae, and a more distinct mesial sinus in the dorsal valve. 

Horizon and Locality: — Common in the Cedar Valley stage of the Devonian^ 
along Mill Creek, near Milan, where it occurs a few feet below the Acervularia 
davidsoni coral reef. 

PUGNOIDES SUBOVATA N. SP. 
Plate II. Figures 5, 6 and 7, 

Description: — Shell broadly subovate to subtrigonal in outline, width and 
length about equal, the greatest width slightly anterior to the middle of the 
shell. The dimensions of 6 individuals range as follows: Length 8 to 10 mm., 
width 8 to 10.5 mm., thickness 5 to 8 mm. 

The ventral valve is less convex than the dorsal except at the front, the 
posterolateral margins nearly straight, and meet at the beak at an angle of 
nearly 90 degrees, the lateral and anterior margins rounded; the surface is 
convex in the umbonal region-, curving abruptly to the posterolateral margins, 
and less abruptly in the anterolateral portion. The beak is pointed, not greatly 



PAPERS ON GEOLOGY AND GEOGRAPHY 



203 



produced beyond that of the dorsal valve, only slightly incurved, closely ap- 
prised over the beak of the opposite valve so as to conceal the foramen; 
mesial sinus obsolete in the posterior part of the shell, but becomes rather 
broad and deep in the anterior portion where it is produced in a rather broad 
linguiform extension that curves strongly towards the dorsal valve. The 
anterior part of the shell bears low, rounded plications of which 3 to 5 are 
depressed in the mesial sinus, on each side of which 3 weak ridges are visible 
for a short distance on the antero-lateral slopes. 

Dorsal valve more convex than the ventral, the greatest convexity along the 
middle part, from which the surface curves rather steeply to the postero — and 
antero — lateral margins, and much less strongly towards the front margin; a 
broad, low, mesial fold appears in the posterior half of the shell, becoming well 
defined, and distinctly elevated at the front where it receives the extension of 
the opposite valve; near the front are a few low, rounded radiating ridges, 4 
to 6 of which are elevated on the mesial fold which is well defined, and is 
bordered on each side by 2 or 3 weaker ridges, none of which extend to the 
middle of the valve. 

Besides the short, low, rounded, radiating ridges and furrows, the surface is 
marked by numerous fine concentric lines which are visible with a lens; a few 
stronger lines of growth are also usually present. 

Remarks: — This shell is easily distinguished from Pugnoides pugnu*. and 
Pugnoides pugnus var. alta, in the weak and rounded character of the radiating 
plications, in whirh characters it more closely agrees with forms like Pug* 
noides ottumwa of the Ste, Genevieve limestone, of Mississippian age. It 
differs from the latter species in being much shorter and thicker in proportion 
to its length. 

Horizon and Locality:— It occurs abundantly in the Cedar Valley limestone* 
a few feet above the Acervularia davidsoni coral reef, about two miles east of 
Andalusia, in Rock Island County, Illinois. 

CRANAENA SUBOVATA N, SP, 

Plate IL Figures 9 and 10. 

Description; — Shell subovate to subtriangular in outline, longer than wide. 
the greatest width anterior to the mid-length, the posterolateral margins 
nearly straight, converging to the beak at an angle of about 75 degrees; an- 
terolateral margins rather strongly and regularly rounded, front margin trun- 
cate or nearly straight* The dimensions of a shell of about average size are: 
Length of ventral pedicle valve 17 mm.; of dorsal valve. 14.5 mm., greatest 
width 14 mm-, convexity 9.5 mm. 

Surface of ventral valve arched along the meridian line from beak to front, 
the greatest convexity slightly posterior to the middle where a faint depression 
appears, and increases in prominence toward the anterior margin where it 
forms a broad, shallow, poorly defined mesial sinus. In the posterior part of 
the shell the transverse curvature is rather strongly convex, being inflected a 
little toward the cardinal extremities; the curvature is more gentle on the 
anterior and antero-lateral portions of the valve; the beak is truncated, not 
strongly incurved, perforated with a moderately large foramen; delthyrium 
concealed by the beak of the opposite valve* 

Dorsal valve about as convex as the ventral, the greatest convexity posterior 
to the middle, gently arched from the beak to the front margin; the transverse 
convexity greatest in the posterior portion, the surface curving rather steeply 
from the median line to the cardinal and lateral margins, and more gently over 
the anterior and antero-lateral areas: no mesial fold or sinus present; beak 
pointed, and incurved beneath that of the ventral valve. 

The surface of both valves is marked by numerous, well defined concentric 
lines of growth which vary in number, strength, and distribution in different 
shells, Shell structure punctate. 



204 ILLINOIS STATE ACADEMY OF SCIENCE 

Remarks: — This species is more closely related to Cranaena iowensis, de- 
scribed by Calvin from the Cedar Valley limestone in Fayette County, Iowa, 
than to any other known species* At the type locality in Iowa the shells of 
Cranaena iowensis are commonly much larger than the most of those belonging 
to that genus at the Illinois locality from which our specimens were collected. 
Besides the smaller size the shells of our species are much more triangular in 
outline, the beaks more attenuate, and the greatest width of the shell much 
farther anteriorly than in Cranaena iowensis. Associated with Cranaena subo- 
vata are shells which in form resemble Cranaena iowensis, and are referred 
to that species although they are much smaller in size. 

Horizon, and Locality: — Abundant in the Cedar Valley limestone a few feet 
above the Acervularia davidsoni coral reef, a short distance west of Andalusia, 
in Rock Island County- 

CRANAENA ELLIPTICA N. SP. 

Plate II, Figures 3 and 4, 

Description:— Associated with Cranaena subovata* and Cranaena iowensis 
at the locality last mentioned are shells belonging to the genus Cranaena 
which differ from either of the above mentioned species in their more elliptical 
outline, the greatest width being at or posterior to the mid-length; the cardino* 
lateral margins are straight, and form an angle of about 90 degrees at the 
beak. An average individual has a length of 15 mm., a width of 14 mm, and 
a thickness of 10 mm. The surface is marked by numerous, rather fine con- 
centric lines near the front and lateral margins, the anterior margin is trun- 
cated, and there is no trace of mesial fold or sinus. These shells have every 
indication of being fully grown and it is proposed to designate them by the 
name of Cranaena elliptica. 

CRANAENA MAXIMA N. SP. 

Plate IL Figure II. 

Among the shells of the species of Cranaena above mentioned there are 
occasionally found shells that rather closely resemble Cranaena iowensis 
in outline, but are readily distinguished from any described species of the 
genus by their very large size. The individual figured measured 40 mm. 
long, 32 mm. wide, and 15 mm, thick. Such shells may be approximately 
referred to as Cranaena maxima. 

CYPRICARDINIA ORNATA N. SP. 
Plate II, Figure 8. 

Description: — -Shell small, subquadrate to rhombic-ovate in outline; hinge 
line straight, about half the greatest length of the shell; beaks situated near 
the anterior margin, directed forward, incurved so that they rise but slightly 
above the hinge line. The right valve is rather strongly convex; the anterior 
end short, concave immediately below the beaks, rounding to the basal margin 
which is straight or very gently convex, and slightly indented a little anterior 
to the middle. The postero-ventral extremity rounded, above which the pos- 
terior margin is obliquely truncate, the surface is most convex in the umbonal 
region from which it curves rather steeply to the front margin, and more gently 
towards the hinge line; a shallow depression with poorly defined borders ap- 
pears near the beak and extends obliquely over the somewhat flattened umbo 
and on to near the middle of the basal margin* A rather prominent elevation 
extends from the dorsal or posterior margin of the umbo obliquely backward, 
with decreasing prominence to the postero-basal extremity of the valve; from 
this elevation the surface curves rather steeply towards the dorsal margin where 
the shell is somewhat flattened. 

The surface of the valve is marked by prominent } somewhat unequal con- 
centric lines, about 5 mm. apart. The concentric lines, and less distinctly the 
separating furrows, are crossed by two sets of fine striae, one set of which ap- 



PAPERS ON GEOLOGY AND GEOGRAPHY 



205 



pears to radiate from the beak, and the other set crosses the first with a curva- 
ture that trends forward and downward from the vicinity of the beak, crossing 
the first set at an angle somewhat less than 90 degrees. 

The left valve was not seen. 

The dimensions of the type are: Length 9 mm,, height 5 mm., thickness of 

right valve 3 mm. 

Remarks: — This shell is most nearly like Cypricardinia indenta Conrad, from 
the Hamilton of New York and the East, from which it differs in the smaller 
size, the greater height in proportion to the length, in the less extended postero- 
ventral border, the shorter hinge line, and in the peculiar ornamentation of the 
surface of the shell. 

Horizon and Locality:* — It occurs in the Cedar Valley stage of the Devonian 
near Andalusia, in Rock Island County, where it is associated with the species 
of Cranaena above described. 

POTERIOCERAS GIGANTEA N. SP. 

Plate III. 

Description: — Shell large, subelliptical to ovate in cross-section, somewhat 
curved throughout, the curvature slight on the concave side, but rather strong 
on the convex; the greatest curvature is a short distance posterior to the base 
of the body chamber. The length of the preserved part of the shell is 18 
inches, the diameter of the posterior end of the specimen is 2 inches, several 
of the lower chambers having been lost* The length of the entire shell must 
have exceeded 20 inches. The shell is somewhat flattened in the direction of 
the curvature; the largest part of the shell is at the second septum posterior 
to the body chamber where the greatest diameter is 7 inches and the smallest 
diameter is nearly 4^2 inches. Posterior to this the greatest width decreases 
rather uniformly at the rate of 2^4 inches in a distance of 6 inches* The 
septa are moderately concave, the average width of the chambers in the larger 
part of the shell is 3/5 of an inch, and the average width of the posterior 3 
inches of the shell is 1/3 of an inch. The body chamber is 4j^ inches long, 
and has a greatest width of 6^4 inches at the posterior end. Anteriorly the 
width decreases slightly, being a little more than 5 inches at the place of 
greatest constriction immediately below the aperture. The aperture is mostly 
concealed, but it is produced somewhat in the direction of thg greatest diameter 
of the shell. The size and position of the siphuncle are not clearly shown, and 
the surface markings of the shell are unknown. 

Remarks: — This form differs from every other species of the genus known 
to the writer in its very large size. In shape it somewhat resembles Poterioceras 
hyatti Whitfield, but the latter is much smaller, and is considerably wider in 
proportion to its length. The relation of the greatest width and the greatest 
curvature is also different from that of the species above described* 

Formation and Locality: — Occurs in the upper part of the Wapsipinieon 
limestone, a short distance above the strongly brecciated bed, in the old 
quarry at Sears, near Rock Island, Illinois, 

RHYTICERAS ORNATA N. SP. 

Plate IV. 

Description: — Shell rather large, regularly expanding, loosely coiled in a 
little more than two volutions; the greatest diameter is 10J4 inches; in the 
internal cast the distance between the volutions in the middle portion is about 
Y% inches, but the w r horls approach to about % inch apart towards the body 
chamber. The transverse section is subcircular or slightly elliptical, the lateral 
diameter being a little greater than the dorsi* ventral. The greatest diameter of 
the whorl (cast) is slightly more than 2 J /i inches; the original shell was 
doubtless 3 inches in diameter. The greater part of the body chamber is lack- 
ing in our specimen, and the aperture can not be seen* The septa are smooth, 
their concavity about equalling the depth of the chambers, which is about Y% 
of an inch near the aperture of the shell, and about J4 i fl ch near the middle, 



206 ILLINOIS STATE ACADEMY OF SCIENCE 

the depth gradually decreasing from the aperture toward the apex, The 
position of the siphuncle is not clearly shown in our specimen, but appears to 
be small, and situated near the ventral side, not enlarged in the chambers 
between the septa* 

The surface is ornamented by a row of prominent nodes or spinous projec- 
tions about one inch apart along each side, which also appear to mark the 
position of transverse ridges. Traces of a third row of spines or of a longi- 
tudinal ridge appear along the ventral margin of the shell. On the dorsal 
surface of the outer whorl there are preserved in some places rather prominent 
longitudinal lines or ridges % to Y% inches apart ; such longitudinal markings 
probably covered the entire surface of the shell. Numerous fine lamellose lines 
of growth, some of which appear to be stronger than others, are also conspic- 
uous on the portions of the shell that are preserved. 

Remarks: — In the surface ornamentation this form is readily distinguished 
from any other known species of Rhyticeras* It differs from Rhyticeras cyclops 
Hall in the more gradual enlargement of the whorls, the stronger transverse 
ridges, more prominent nodes along the lateral and ventral margins, and in the 
finer longitudinal surface markings. From Rhyticeras spinosum Hall it is 
distinguished by the stronger longitudinal ornamentation, and less rapid ex- 
pansion of the anterior part of the shell. 

Formation and Locality: — This species occurs in the upper part of the 
Wapsipinicon limestone where it is associated with Gypidula comis, Poteri- 
oeeras gigantea.. and Rhyticeras barrisi, near the village of Sears, in Rock 
Island County, Illinois. 

EXPLANATION OF PLATES 

PLATE I. 

Figures 1 and 2, Diplophyllum? major n t sp. Transverse section of two 
corallites magnified a little more than two times; and view of a fragment of 
corallum, natural size. 

Figures 3 and 4, Zaphrentis put ilia n. sp. Longitudinal view showing 
septal ridges; and transverse section of a corallite. Both one and one-half 
times natural size, 

plate n. 

Figures 1 and 2, Rhipidomella minima n. sp. Ventral and dorsal views 
of the type specimen. A little more than twice natural size. 

Figures 3 and 4. Cranaena elliptic a n, sp. Dorsal and ventral views of 
the type; magnified about two times the natural size. 

Figures 5, 6 and 7, Pugnoides subovata n, sp, Ventral, dorsal and front 
views of a typical specimen. Twice natural size* 

Figure 8. Cypricardinia ornata n. sp. View of the right valve of a nearly 
entire specimen; enlarged a little more than two times. 

Figures 9 and 10, Cranaena subovata n. sp. Ventral and dorsal views of the 
type specimen. Enlarged two times. 

Figure 11. Cranaena maxima n* sp. Dorsal view of a typical specimen. 
About twice natural size. 

PLATE III. 

Figure 1. PoterioceTas gigantea n. sp. Longitudinal view of the type 
specimen. A little less than one-half natural size. 

PLATE IV. 

Figure 1. Rhyticeras ornata n, sp. View of one side of an exfoliated 
specimen. About one-half natural size.